Roadway, paving block, and the like



Nov. 17, 1925- G. 0. CASE ROADWAY, PAVING BLOCK, AND THE LIKE Filed Sept. '7, 1923 kiwi/v01? 50mm 0725) C455. 1*" "5 7 Armkuzx Patented Nov 17, 1925.

UNITED STATES PATENT OFFICE."

GERALD OTLEY CASE, OF LONDON, ENGLAND, ASSIGN OR TO RUIBACRETE LIMITED, OF

LONDON, ENGLAND. I

ROADWAY, PAVING BLOCK, AND THE LIKE.

Application 'filed September 7. 1923. Serial Nu. 661,524.

To all whom it may conocm:

Be it known that I, GERALD OTLEY CAsE, a subject of the King of Great Britain, residing at 7-8 Idol Lane, Great Tower Street, London, E. C. 3, England, have invented certain new anduseful Improvements in oadways, Paving Blocks, and the like, of which the following is a specification.

This invention relates to improvements in or relating to paving material, for example, paving blocks, more particularly for the construction of roadways, pavings, and such-like: though mentioned as relating to paving blocks, the invention also relates to large surfaces in which rubber sheeting is required to be attached to a supporting surface, for example, for courts or other surfaces for playing games, in domestic archif tecture, and generally in any cases where it is desired that a rubber surface should be attached to a supporting surface, such for example, as concrete. y

In the making of such articles as blocks for roadways, or roadways with large 'surf canizing the lower layer of the rubber top, in order to render it comparatively hard.

The object of this invention is to obviate failure due to rubbing, and especially to ensurethat in dealing with materials composed of ruhheriin association withmineral surfaces. frictional wear is prevented in a v simple manner.

It has heretofore been proposed where a rubber layer is associated with concrete, To provide studs or projections of a kind which are pressed into the concrete while plastic, but so far as I am aware, this has only been suggested where considerable areas of concrete areleft betweenthe projections, which I have found by experiment is a serious defeet,

According to this invention, in carrying out the association of the rubber layer with the concrete support, I provide pins or simieach pin is thus securely lar projections (preferably circular-in crosssection) formed beneath and integrally with the rubber layer, vwhich directly enter the substance of the concrete, but distinguished by the feature that at the definite joint between the main rubber surface and the main cement or concrete surface there should be i about thesame area of rubber pins entering the concrete as there is of unperforated concrete, the distribution of the pins being limited by the fact that the area of rubber layer overlying the top surface of the concrete shall be such that it will prevent any possibility of the rubbing ofthe rubber on the concrete due to the passage of vehicles,

or otherwise, so that the friction between the surfaces thereby engendered wears the concrete. a Y

The 'concrete is advantage of the'important condition that when setting in air the cement shrinksand gripped when the cement finally sets.'

In practicethis resolves itself into having the pins or the like of rubber of small area close together, with the governing consideration that they shall not be so small that the action to which they are subjected shears the pins from the rubber layer, this consid-eration being combined with the condition that sufliciently reduced areas between the rubber projections are present to preset inair in order to take veut friction, due to traffic causing wear atthe dividing level. 7

I am aware that it has previously been proposed to constructa pavement wherein tiles of rubber are provided with an integral stud or studs by tapping them into a layer of cement while the latter is, .in a plastic condition, but I point out that it is exceedingly doubtful ifit is practicable to get the cement in such a case to grip the said studs satisfiiu'rtorily, and the rubber would certainly need to be held under pressure therein for some considerable time whiletheconcreic sets; in any case, so far as I am aware. it has not previously been proposed to reduce the'area of concrete between the studs tance.

It should be understood "that cement and concrete are used 'herein as synonymous terms, and depend merely on the particular mixture employed in particular cases. The accompanying drawings illustrate the invention:

v Fig.1 is a View partly in section showing a layer of rubber provided with the projecting pins in elevation and attached'to a block of concrete; y

Fig. 2 is a plan ofthe rubberv layer from the1 under side, showing the pins in plan, an

Fig. 3 illustrates a method'of producingpaving blocks in a mould.

Referring to the draw1ngs, '-Fig. li -is a of the total area'of the rubber layers, that is, when finally, attached to j the cementor concrete base. there 'wouldbe about threeeighths of entering rubber-to five-eighths of cement'surface where the rubber and cement surf-aces" meet, the distribution of flle. cement'surface being such that there will be no considerableareaat the dividing level which will allow of the' rubber-layer being 7 rubbed on the cement surface.

In certain. cases it may be desirable to make the outer line 3 of rubber pins so1nc-.

what largerithan the. innermost pins, as

it is required that these shouldbe as near.

as possible to the edges of the block and rather more strain on the rubber pins will possibly take place at the edges of th block than in the middle.

In regard to the construction otthe pins 1 2, it shouldbe noted thatthe layer 1, with its pins attached, has'first to be made bc fore application tothe base material, and

usually the rubber facing must-be made by I casting it in .a mould, or perhaps forcing it into a mould while the rubber is plastic. Careful consideration there-fore =must be given to getting the rubber layer out ot itsmould when formed, and one-sixteenth' of an inch diameteris, about the n'iinimumlimit at which the pins can be withdrawn from tlm mould, besides bein-gahout the minimum limitof size whichlwill withstand; the shearing a'ctionwhen traffic comes upon the roadway. In this connection the length of the pins is'also'of some importance, and preferably these should. be made approxi- 'mately three diameters in length.

'By reference to the dotted circles 4 shownin Fig. 2, it will be seen that each pin is completely surrounded by the cement or concrete of the base, and it is due to the shrinkage .of this cement when setting in air that each pin is securely gripped when the cement 'finall sets.

Since the shrin age of the cement depends upon the state of atmosphere in which the setting blocks should be formed under cover, and in Fig. 3 is illustrated a mould 5 suitable for casting a. block, the rubber layer being first placed in the bottom of the mould and thereafter cement, for example, Portland cement, either mixed with sand or not, poured into the mould, which will eventual- 1y harden with the pins 2 firmly embedded therein. Casting 'in'this way has the effect of keeping the densest layer of cement takes place, 'it is advisable that the.

again'sttherubber layer, which is desirable,

and unevenness of surface at the .back of the combined block will be relatively unimportant.

In considering say, a block for a roadway carrying ordinary traflic, the size of the rubber projections which I findsuitable is a diameter varying from about onc eighth of an inch to three-eighths of an inch, and, viewed in plan, with a proportional area of the rubber projections, varying between limits of about three-eighths to five-eighths of the total area of the layer to which they are attached, about half of the pin area to half of fiat area being a useful average.

. Since an essential part of the invention is the gripping of the pins -by the concrete, it is found that with pins of the dimensions mentioned a distributed and effective at tachment is obtained in view of the fact that the area of concrete at the dividing level is also reduced to asufiicient area, and owing to its shrinkage in setting. the pins are tightly and sufficiently gripped. even though formed with parallel sides.

While the best proportions of the pins for normal'trafiic are set out, it should bennderstood that in certain circumstances pins of a slightl smaller, or of a larger size may be emp oyed, for example, where light traflicionly is using the surface, or where a lai' er amount of flexibility of the surfa'ceis rfesirable, subject still, however, to the governing, consideration that each pin should be surrounded by the 'cement" layer, which should, be of small area in; proportion in order thatthere shall be no extended rubber to cement'contacts at the dividing level, and in order to takecadvantage of the contracting character of the ce- I ment when'settin inair.

By reason of. t eformation. of the, nu; merous rubber points and the small area of:

nection, but I may also use cement with particular adhesive qualities in certain cases of difiicult application.

I claim 1. In roadways and blocks for roadways and paving purposes, in combination, a rubber layer and a foundation of cement, or the like, to which the said rubber layer is attached, and means for attaching, comprising numerous pins of relatively small cross sectional area integral with the rubber layer, and of a length substantially greater than their largest width, each pin being com letely surrounded by the said cement, and being equally spaced apart in the said cement in such a manner that the area viewed in plan of the said pins and the area of the unperforated foundation is approximately the same, whereby both shearing of the pins and creep ing, or rising of the layer are prevented.

2. In roadways andblocks for roadways and paving purposes, in combination, a rubber layer and a foundation of cement,or the like, to which the said rubber layer is attached, and means for attaching, comprising numerous pins of relatively small cross sectional area integral with the rubber layer, and of a length at least three times their largest width, each in being completely surrounded by the said cement, and being equally spaced apart in the said cement-in such a manner that the area viewed in plan of the said pinsand the area of the unperforated foundation is approximately the same, whereby both shearing of the pins and creeping of the layer are prevented.-

3. In roadways and blocks for roadways and paving purposes, in combination, a relatively thin rubber layer and foundation of cement or the like to which said rubber layer is attached, and means for attaching s'aid layers comprising numerous pins within vlimits of frmn one-eighth to three-eigh'ths of an inch diameter and .ofa len h substantially reater than the said iameter and integra with the rubber layer, each pin being completely surrounded by the cement,

of the total area ofthe rubber layer.

and the number of said pins and their disposition in the cement,- or equivalent foundations being such that the areas of unperforated foundation lying between the pins are small, substantially as described and forthe of an inch diameter and of a length substantially greater thanthe said diameter and integral with the rubber layer, and occupying an area of from three-eighths to fiveeighths of the total area of the underside of the rubber layer, the number of the said pins and their disposition in the cement or equivalent foundation being such that the areas of unperforatedfoundation lying between the pins are small around each pin.

5. A relatively thin rubber pad or layer for use in making blocks for roadways and paving purposes, having numerous rubber pins within the limits of fromone-eighth tothree-eighths of an inch diameter and of a length substantially greater than the said diameter projeetin, from one side integrally with the" whole rubber layer and occupying an area of from threc-eighths to five-eighths 6. A relatively thinrubbcr pad or layer for use In making blocks for roadways and paving purposes, having means thereon for attaching the layer to a foundation comprismg numerous pins of relatwely small cross sectional area integralwith the rubber layer,

and of a length substantially greater than their largest width. each pin being equally spaced apart in such manner that the areas viewed in plan of hes-aid pins and the areas of the spaces between the pins is approxi- I mately thesame. 

